<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册失败</title>
    <style>
  a {
    text-decoration: none;
      color: #0f0f0f;
  }
</style>
</head>
<body>

<button style="margin-left: 640px;margin-top: 350px;font-size: 30px;font-family: Roboto, serif"><a href="{{ url_for('login') }}">返回登录</a></button>

<script>
alert('注册账号失败，您输入的用户名已存在!')
</script>
</body>
</html>